As a method of assaying effects on living organisms of unknown chemical substances present in the environment, biological toxicity inspection of “bioassay,” by which growth inhibition of bacteria, algae, water flea, fish, or other living organism is inspected, has been employed from before. Bioassay enables comprehensive detection of effects due to unknown substances or unexpected substances, interactions of chemical substances, environmental effects, and other biological effects, and is in a complementary relationship with conventional physicochemical methods such as liquid chromatography, gas chromatography, atomic absorption measurement, and enzyme immunoassay.
In bioassay, single-cell organisms, such as bacteria or algae, which enable a large number of individual organisms to be treated statistically and are short in lifecycle, or small aquatic organisms, such as small crustaceans (water fleas) or small fish, etc., which have comparatively advanced biological functions and yet are readily affected by chemical substances, etc., are used. As a specific example of a bioassay method, a method of biological effect assay by algae growth inhibition test, which is defined in guidelines of the Ministry of Environment of Japan, can be cited. The algae growth inhibition test is a method of assaying various toxicities of a tested substance on algae.
As another method, a method of measuring respiratory inhibition by measurement of luminescence by luminescent bacteria has been proposed. Also, Non-Patent Document 1 describes a method of measuring photosynthesis inhibition using chlorophyll fluorescence from algae. Non-Patent Documents 2 and 3 also describe measurement methods using delayed fluorescence.    Non-Patent Document 1: Ulrich Schreiber et al., “New type of dual-channel PAM chlorophyll fluorometer for highly sensitive water toxicity biotests”, Photosynthesis Research 74, p. 317-330 (2002)    Non-Patent Document 2: Werner Schmidt and Horst Senger, “Long-term delayed luminescence in Scenedesmus obliquus. II. Influence of exogeneous factors”, Biochimica et Biophysica Acta 891, p. 22-27 (1987)    Non-Patent Document 3: Joachim Burger and Werner Schmidt, “Long term delayed luminescence: A possible fast and convenient assay for nutrition deficiencies and environmental pollution damages in plants”, Plant and Soil 109, p. 79-83 (1988)